Sinopoly Cells - Info -

[shirley_hkg]

Run a quick trip to find out shipping quote this afternoon ; 35℃ under the mercyless sun.

Avoid slowing down as far as possible , but only get average speed 15.5km an hour .

Best I can do .

Hat off to snaker , who ran 8 hours non-stop.

[shirley_hkg]

Air freight : £6.75 / kg to UK ; custom fee included . No more extra at all . That's what I've been told.

EVE-LF90 , Rated --- 3C (5C max) ; IR @ 0.5mΩ .

90Ah cell , 2017/8/31 NOS @£27.50

* * * * unknow batch NOS @£18.80

Any guinea pig ? ? ?

[expresso]

hey shirley - maybe i take a shot at them since i havnt ordered any yet for an ADD ON i want to do -

i noticed one cell has the size i can use - 185 x 130 x 30 68ah ? if i am correct - if the total height is no more than 185mm for real - i can use it - 30mm thick is perfect also and up to 145mm wide i can do

if i can get connectors and screws etc, all the hardware - i take a chance and try them - if you dont mind ?


if so - i can use 8 of them

[expresso]

https://sc01.alicdn.com/kf/HTB1UyhGa.z. ... 0nFXaq.jpg

i finally got one seller to set it up for me and final cost would be $631 with shipping - 8 cells with connectors -

is that a good price you think Shirley ?

its 36mm thick which is max i can do - i would have liked 30mm like yours - gives me more

what would it cost if getting the 8 from you ?

[expresso]

quick question -

the C rate of a Cell - lets say its 150A constant discharge rate -

if using 8 Cells - would that mean its 150A x 8 for the total discharge rate for the Pack ?

trying to understand so when i check specs etc, i have a better idea of what Cells to consider - i assume the pack of 8 spreads the load when in use - so in theory a Cell that has a 150A constant discharge rate is suffice to use ?

i know if its higher - its always better - headways 5C -

will using a Cell thats 150A discharge rate be Ok or at least good enough - 8 Cells taking the load - lets say the chair Rnet is using 240A All the time - which it dosnt but even if it did - if 150 x 8 gives you 1200A total - which 240A gets spread out between all 8 Cells when in use ?

is that correct or if not - correct me so i understand

thanks

[Gnomatic]

quick question -

the C rate of a Cell - lets say its 150A constant discharge rate -

if using 8 Cells - would that mean its 150A x 8 for the total discharge rate for the Pack ?

is that correct or if not - correct me so i understand

thanks

Lets say you have 8 x 75Ah cells rated at 2C constant discharge. That's 150A/cell discharge. If you wired all of them together in parallel(+ to +, - to - ...), your pack would be only 3.2v, but would be 600Ah. At 2C for the pack, thats 1200A continuous discharge.(assuming specs are accurate) But again, only a 3.2v pack.

Now, if you wire those same cells together in series(+ to -, + tp - ...), as we need to do for our chairs so the pack has the right voltage, you'd have a 75Ah pack, @24v. The voltage we need. At 2C, that means the pack could sustain 150A discharge.

[Burgerman]

But the higher you go, towards the max discharge the less cycles you will get.

When a pack is rated for say 2000 cycles, it is at anything from 0.1C to 1C depending on tests.
At 2C discharge you may lose half of that, get 1000 cycles. At 3C you may get 500 cycles.

So taking 2C from a 10C pack? Safe!
Taking 2C from a 3C pack, not so clever... $£$£$£$£

This is especially important on a addon, as its small, so you are taking a higher C rate from its cells.

[expresso]

I see. I got it wrong then. Ok bottom line now is. The cell I found is 3C. Says 180 A. Discharge the link I posted above. Is that Ok ?

[Burgerman]

Depends. As an addon? Or as a part of a bigger pack?

It will WORK in both cases. As an addon its OK just about only because its big, at 60Ah, so 3c max? is 3x 60Ah, or 180 max. But those cells wont like it much. They are happier at low dicharge rates.

The headways are 5C continuous, 10C peak.
So a smaller 36Ah headway pack is good for 36Ah x 5 = 180A cont, or 360A peak. So thats safer!

A 60Ah headway could do 5x 60Ah continuous, thats 300A. 600 peak for limited periods. So that keeps us further away from the max they can do, so last longer. This is why the bigger a battery is, the better!

[expresso]

Depends. As an addon? Or as a part of a bigger pack?

It will WORK in both cases. As an addon its OK just about only because its big, at 60Ah, so 3c max? is 3x 60Ah, or 180 max. But those cells wont like it much. They are happier at low dicharge rates.

The headways are 5C continuous, 10C peak.
So a smaller 36Ah headway pack is good for 36Ah x 5 = 180A cont, or 360A peak. So thats safer!

A 60Ah headway could do 5x 60Ah continuous, thats 300A. 600 peak for limited periods. So that keeps us further away from the max they can do, so last longer. This is why the bigger a battery is, the better!

this would be or an ADD ON - to replace the 36ah i had before - now its on Quickiee's chair - i got a price of about 630 for 8 cells shipped - fedex so about 2 weeks if i go for it - - going with headways would give me 45ah max. and alot more money - with shipping etc, -

i did want to try this kind - size wise - makes it easier to build - 8 cells etc, -

Shirley been getting over 5 years with his ADD ON's i believe if not more - cant be to bad ?

[Burgerman]

Should be OK, the lead helps too.

[expresso]

Should be OK, the lead helps too.

ok - i am ready to act on this one - i did email this seller back to ask for a 5C Cell if she can find one -

GTK - i found this one which says 5C BUT if you look at the picture - its the same Cell the Frey which says 3C - its very tricky how they post pictures and specs - cant be sure what i would get if ordered these instead

i know for sure the Frey model is 3C - brand new - with connectors etc, - shes been very nice and got it all ready for me to just click buy and pay - i did ask just in case if she can get this GTK model if its really 5C - i am warry and cost would be more unless i want it by boat

the quote i got was for Fedex shipping in 2 weeks - isnt bad at all i dont think


https://www.aliexpress.com/item/1pc-Lif ... 2e0ekqdatW

lead i got new and never used it alone always had the ADD ON - now i dont want to use it with out an ADD ON - it wont be used much since i am expecting a new chair in a few months - - i got approved for the boulder - like it or not - with lithium 100ah - and thinking of adding an ADD ON there also

[shirley_hkg]

goodpost Air freight : £6.75 / kg to UK ; custom fee included . No more extra at all . That's what I've been told.

EVE-LF90 , Rated --- 3C (5C max) ; IR @ 0.5mΩ .

90Ah cell , 2017/8/31 NOS @£27.50

* * * * unknow batch NOS @£18.80

Not interested at all ? John .

[Burgerman]

Yes but cant do it right now... £££

[shirley_hkg]

Can bill you later .

[Burgerman]

Right now I have a list...
I had a leak. 3 large carpets, decorate and renew woodwork and plaster, new sofa etc.
New motor on BM3...
And many smaller things!
Like gas, electric, water...
And I am on bed with a stupid bladder infection.

But thanks anyway!

[shirley_hkg]

One way to ease your worry about over-stressing a low C add-on is to put a diode in its discharge path .

-0.6V will match the discharge platform of MK gel perfectly .

Didn't you hear BM mentioned before ?

[expresso]

i have no idea if i heard BM say it before or not - i am not that tech. to do all kinds of things like you are -

Shirley what do you think of those Cells i found ?

the ones you found - how much would it cost US dollars for 8 - 68ah model ?

i was ready when i got response for the others Frey model -

[Gnomatic]

Hi shirley.

Can you still get cells like this

https://item.taobao.com/item.htm?spm=a2 ... =14#detail

or this?

https://item.taobao.com/item.htm?spm=a2 ... =14#detail


I'm interested if so, and can still ship to US.

[Burgerman]

Yes a 100/200A heavy diode in series with the lifepo4 cable saves the lithium, and uses more lead. So you dont just lean on the add-on most of the time. Also means the battery meter will make more sense.

Say 2x these in parallel, would do it. They will drop .7V approx, so your lithium will be 25.6 less .7 = 24.9V most of the day.
https://www.ebay.com/p/50-X-Vishay-Powe ... 1021668224

[shirley_hkg]

Haven't replied me about shipping to US yet .

[Gnomatic]

Thanks for checking!

[expresso]

Yes a 100/200A heavy diode in series with the lifepo4 cable saves the lithium, and uses more lead. So you dont just lean on the add-on most of the time. Also means the battery meter will make more sense.

Say 2x these in parallel, would do it. They will drop .7V approx, so your lithium will be 25.6 less .7 = 24.9V most of the day.
https://www.ebay.com/p/50-X-Vishay-Powe ... 1021668224

Oh thats nice - didnt know - i still not sure how i would connect them -

cable is already made - i most likely wont do it now - but on a new cable if i have to make one again - i solder one of these in between the Pos. cable like a fuse ? and do the same to the Neg. cable - and thats it ?

[Burgerman]

In one end, out the other!

[expresso]

In one end, out the other!

you mean solder it between the cable both ends - like a fuse ?

i dont see where it would go inside - i see a screw on one end - giving me the impression it needs to be screwed in something

and i just pulled the trigger on some Cells from Aliexpress - - free shipping so i am looking at July before i get them - hope they are as they stated with specs etc, it shows 5C constant discharge - i emailed to ask and was told yes 5C - peak 600A -

hope i get the connectors also - never got an answer to that one -

Oh wait you mean solder the cable thru the hole on top ? disregarding the screw ?

[Burgerman]

If fitted like a fuse it will get hot and fail. So one end is threaded so it can screw into a lump of aluminium, or a heat sink. Then the heat sink is the other wire...



Heres 2 fitted to a big heat sink...

[Burgerman]

This also means that any regeneration current will be blocked, so it will all go into the lead. A diode is like a one way valve. Like a tyre valve. Electricity can only go one way. In the soldered part, out of the bolt / thread (ring terminal). But it also needs a heat sink.

But it loses .6 to .7 of a volt. So we will be using its normal disadvantage to our advantage.

[expresso]

Ok so i am wrong again - and yet not clear to me how it will go between the cable -

the cable we are talking about also is the POS and NEG coming from the ADD ON pack - ? this is where this item should go ?

i see how they are fitted to the heatsink - in this case - there wont be a heatsink or anything other than the cable wire ?

i cant vision any other way than what i though with the wire going thru the HOLE on the top - according to the pictures its not that way - but dont see how it would be done for the ADD ON cables

[expresso]

This also means that any regeneration current will be blocked, so it will all go into the lead. A diode is like a one way valve. Like a tyre valve. Electricity can only go one way. In the soldered part, out of the bolt / thread (ring terminal). But it also needs a heat sink.

But it loses .6 to .7 of a volt. So we will be using its normal disadvantage to our advantage.

ah ok - so i am correct then if you solder the wire on the HOLE on top and then solder on the bolt or ring terminal - thats inline with the cable - but if you need a heat sink to make this work - then what ? i have to add a heatshink also ?

wouldnt that be so bulky -

in any event the cells i ordered are 5C - maybe wont need to worry then too much -

do you have any thing already made with this inline to show a picture of how it needs to be - ? pictures work wonders

[Burgerman]

Bulky? Yep a bit. You will be fine without.